1. Field of the Invention
The disclosure relates generally to a non-volatile semiconductor memory device, and more particularly, to a memory block of a NAND flash memory.
2. Description of the Related Art
Flash memories are broadly used in storage devices, and electrical devices, such as digital cameras, and smart phones. Current flash memory demand functionalities include small sizes, high capacities, high speeds, and low power consumption. In addition, flash memories having fixed times and the data holding is also needed.
A NAND flash memory comprises a memory array formed by a plurality of blocks, wherein the plurality of blocks is formed by a plurality of NAND strings arranged in a row. The NAND string has selection transistors coupled to each of two terminals of memory cells connected in series, wherein one terminal is connected to a bit line via the selection transistor, and the other terminal is connected to a source line via the selection transistor. Data reading or writing (programming) is performed via the bit line connected to the NAND string, such as the flash memory with improved data programming speed as disclosed by Patent Document Japan Patent Publication No. 2006-302960.